Wheel loaders, track loaders, and other loading machines are equipped with buckets for the purposes of digging, loading, and transporting all manner of different materials. One particular type of loader, an underground loader, or load, haul, dump machine (LHD) is adapted to perform these functions at underground mining sites, which can present smaller, more confined work spaces than surface-level operations. Despite the varying logistical difficulties presented at various different mining sites, common to most is that materials in a loose state such as ore, rock and gravel must be moved around and often among different machines for transport and processing. One typical loader application at mine sites is the loading of blasted rock such as ore or overburden into a truck for disposal or transport to a processing site, or delivery of ore directly to a crusher. U.S. Pat. No. 4,633,601 to Fleck et al. is directed to a “shovel” that appears suitable for use in loader applications, and having pivotally interconnected back and front sections, and a torque tube apparently supported by bushings and structured for coupling the shovel to lift arms or the like in an implement system.
As suggested above, underground access is typically relatively limited, often resulting in narrow passageways, low clearances, and other difficulties. While loaders for surface mining and underground loaders share many features, underground loaders and related equipment are often purpose-built to meet the logistical challenges of underground excavation, typically having heavy planetary axles, four-wheel drive, and articulated steering to maximize maneuverability while having a narrower, longer, and lower profile in order to fit into tight access points. The latter of these adaptations extends not only to the body of underground loaders but also to its operational features such as the bucket and linkage.